HIGH-ENERGY MIXTURES
Compounds containing both a readily-oxidizable and a readily- reducible component within one molecule are uncommon. Such species tend to have explosive properties. A molecule or ionic compound containing an internal oxidizer/reducer pair is inherently the most intimately-mixed high energy material that can be prepared. The mixing is achieved at the molecular (or ionic) level, and no migration or diffusion is required to bring the electron donor and electron acceptor together. The electron transfer reaction is expected to be rapid (even violent) in such species, upon application of the necessary activation energy to a small portion of the composition. A variety of compounds possessing this intramolecular reaction capability are shown in Table. The output from the exothermic decomposition of these compounds is typically heat, gas, and shock. Many of these materials detonate - a property quite uncommon with mixtures, where the degree of homogeneity is considerably less.
The high-energy chemist can greatly expand his repertoire of materials by preparing mixtures, combining an oxidizing material with a fuel to produce the exact heat output and burn- ing rate needed for a particular application. Bright light, colors, and smoke can also be produced using such mixtures, adding additional dimensions to the uses of high-energy materials. For these effects to be achieved, it is critical that the mixture burn rather than explode. Burning behavior is dependent upon a number of factors, and the pyrotechnist must carefully control these variables to obtain the desired performance. Pyrotechnic mixtures "burn," but it must be remembered that these materials supply their own oxygen for combustion, through the thermal decomposition of an oxygen-rich material such as potassium chlorate
Thus, a pyrotechnic fire can not be suffocated - no air is needed
for these mixtures to vigorously burn. In fact, confinement can accelerate the burning of a pyrotechnic composition by producing an increase in pressure, possibly leading to an explosion. Ade- quate venting is quite important in keeping a pyrotechnic fire from developing into a serious explosion. A variety of ingredients, each serving one or more purposes, can be used to create an effective composition.
Compounds Containing Intramolecular Oxidation - Reduction Capability
Note: These compounds readily undergo explosive decomposition when sufficient ignition stimulus is applied. A shock stimulus is frequently needed to activate the nonionic organic molecules (e.g., TNT) ; these compounds will frequently merely burn if a flame is applied.